1. Technical Field
The present invention relates to semi-permeable membranes and more particularly to a semi-permeable nanoporous membrane and methods for making and using the same for desalination and other processes.
2. Description of the Related Art
Water desalination may be thought of in terms of two approaches. The two basic approaches for water desalination include reverse osmosis and distillation. The distillation approach requires converting fluid water to the vapor phase and condensing water from the vapor. This approach is fairly high cost and requires significant energy usage. The reverse osmosis approach uses pressure on a salinated liquid to force water molecules through a semi-permeable membrane. This approach has a relativity low rate of energy consumption.
The specific (per unit of produced potable water) energy of desalination using reverse osmosis has been reduced from over 10 k Wh/m3 in the 1980s to below 4 k Wh/m3, approaching the theoretical minimum required energy of 0.7 k Wh/m3. To improve the state of art of the reverse osmosis approach, new membranes, with a uniform pore distribution and a more permeable separation layer can potentially maintain or improve salt rejection while increasing the flux in the reverse osmosis method. Such improvements have not yet been developed in the conventional art.